How severe is CVE-2026-27737?

CVE-2026-27737 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-27737 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-27737?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-27737 have an EU (EUVD) identifier?

Yes. CVE-2026-27737 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30811.

When was CVE-2026-27737 published?

CVE-2026-27737 was published on 2026-05-18 and last updated on 2026-06-17.

CVE-2026-27737

CVE-2026-27737 is a medium-severity vulnerability with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-30811
Weakness: CWE-79
Published: 2026-05-18
Last modified: 2026-06-17

Description

BigBlueButton is an open-source virtual classroom. In versions prior to 3.0.19, the recording playback (presentation format) was not sanitizing user's input in public chat. This allowed for a malicious actor to craft and carry out a targeted XSS attack, activated on anyone replaying the recording. This issue has been fixed 3.0.19.

Frequently asked questions

What is CVE-2026-27737?: BigBlueButton is an open-source virtual classroom. In versions prior to 3.0.19, the recording playback (presentation format) was not sanitizing user's input in public chat. This allowed for a malicious actor to craft and carry out a targeted XSS attack, activated on anyone replaying the recording. This issue has been fixed 3.0.19.
How severe is CVE-2026-27737?: CVE-2026-27737 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-27737 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-27737?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-27737 have an EU (EUVD) identifier?: Yes. CVE-2026-27737 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30811.
When was CVE-2026-27737 published?: CVE-2026-27737 was published on 2026-05-18 and last updated on 2026-06-17.

References

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